Low-friction speed-responsive sensor for elevator



W4 H. LEITZ April 23, 1968 LOW-FRICTION SPEED-RESPONSIVE SENSOR Filed Feb. 28, 1964 2 Sheets-Sheet 1 5 V m w w W 7 I 3 0 ,V W W V fi u um C V 0 Kw w m m V}? w l M if am 4 /D LU I I. 2 S "a 3 Z O G 9 W02 2 2 VE wM S r bf" R C 8 D 5 I u 9 s r 1 2 c 2 1T 75. a 2 6 w! L 7 2 f a 2l2 m (2 7 Tm u ,W 7 I rm: 9 9 2 I M: a; a N F .II I 5 9 5 "Q 3 W 4 Qfi 2 2. 3 m 3 R R. w: Mfifi m 2L? 8 2 2 2 E E 551:

INVENTOR William H. Leitz Viz? ATTORNEY United States Patent ABSTRACT OF THE DISCLOSURE Application of a vehicle brake is supervised by a lowfriction speed-responsive device which is effective when the vehicle is in a predetermined region, such as a terminal region, to apply the brake.

This invention relates to vehicular control equipment and it has particular relation to equipment for controlling the movement of a vehicle in a predetermined portion of travel.

The invention is applicable to vehicles which are constrained for movement in predetermined paths which may be horizontal or inclined from the horizontal. In a prcferred embodiment, the invention is incorporated in an elevator system.

In conventional practice an elevator is constrained for movement in a vertical path between upper and lower terminal floors. To guard against overtravel of the elevator it is the practice to employ terminal slowdown or stopping equipment which assures slowdown and stopping of the elevator should the elevator attempt to operate in a terminal region above a predetermined speed. Positive and accurate control of the elevator in such a terminal region has been difficult to achieve in the prior art particularly for elevators operating at high speeds such as speeds of the order of 1,000 feet per minute or higher.

In accordance with the invention an elevator is provided with a speedresponsive device which has extremely low friction. The speed-responsive device includes a driving element which is operated in accordance with the actual elevator speed and a driven element which is driven by the driving element through a fluid coupling. In a preferred embodiment of the invention the coupling is effective by moving an electroconductive armature relative to a magnetic field for the purpose of establishing a coupling of the eddy-current type.

Displacement of the driven element from a predetermined position is employed for operating electrical switches of a type requiring low operating forces. In a preferred embodiment of the invention mercury switches are employed.

The invention also contemplates protection against failure of the drive for the driving element. In a preferred embodiment of the invention the speed responsive device is rendered etiective to modify the operation of the elevator only when the elevator car is in a predetermined region such as a terminal region.

It is therefore an object of the invention to provide vehicular control equipment having accurate and positive operation.

It is a further object of the invention to provide vehicular control equipment having low friction.

Other objects of the invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a schematic view illustrating one embodiment of the invention;

FIG. 2 is a schematic view showing circuits employed in the embodiment of FIG. 1;

FIG. 3 is a View in sectional elevation of a speedresponsive device employed in the embodiment of FIG. 1; and

3,379,285 Patented Apr. 23, 1968 FIG. 4 is a view in rear elevation with parts broken away of the speed-responsive device shown in FIG. 3.

In order to simplify the presentation of th invention the invention will be described as applied to an elevator system similar to that shown in the Oplinger Patent 2,874,806, which issued Feb. 24, 1959. FIG. 1 is a reproduction of FIG. 4 of the aforesaid Oplinger patent with certain additions shown in heavy lines. For convenience certain components of FIG. 1 which also are shown in the Oplinger patent are listed in the following table:

Apparatus table 1 Elevator motor. 3 Penthouse floor.

Traction heave. Elevator brake. Speed control unit. Elevator car.

.. Rope.

Electromagnetic unit. inductor plate.

BR Auxiliary relay. TR2-TR5 Transfer relay contacts. B1, B2 Direct-current buses.

1H5 Control-unit levcr.

P i Pattern motor.

MA Elevator motor armature. MP Elevator motor field winding. 215 Electroconductive disc. G Generator.

239, 241 Rheostats.

GFi, GR. Generator field windings. UM, DM Solenoid control units.

Full-wave rectifiers. Transformers.

As shown in FIG. 1 an elevator brake 7 is forced against a brake drum by means of a mechanical spring to prevent movement of the elevator car 11. When th elevator car is to be moved the brake 7 has its solenoid energized from direct-current buses Bi and B2 through make contacts 32-1 or R1. This results in a release of the brake to permit movement of the elevator car.

In accordance with the embodiment of the present invention shown in FIG. 1, a safety relay SR is employed for supervising the operation of the brake 7. In this embodiment the brake 7 can be energized for the purpose of releasing the brake only if a set of make contacts SR1 of the safety relay SR are closed to permit energization of the brake from the buses B1 and B2. If the safety relay SR is deenergized and dropped out the contacts SR1 are opened to prevent encrgization of the brake 7. In addition the safety relay SR has a set of make contacts SR2 in the loop circuit connecting the armatures GA and MA of the generator and motor. Consequently, the motor armature MA can be energized to move the elevator car only if the contacts SR2 are in closed position.

If the sets of contacts SR1 and SR2 of the safety relay SR are blocked in their closed conditions the elevator system illustrated in FIG. 1 operates precisely in the same manner as the elevator system of the aforesaid Oplinger patent and reference to such Oplinger patent may be made for a detailed discussion of such operation.

Dropout of the safety relaySR is employed for assuring slowdown and stopping of the elevator car under certain conditions wherein movement of the car is not desired. To this end as shown in FIG. 2 the operating coil of the safety relay SR is connected between the direct-current buses Bi and B2 through any contacts which are intended to control the operation of such relay. Thus if the speed of the elevator car is above a certain value the contacts CSD1 of a car speed device CSD open to deenergize the safety relay SR.

It is often desirable that such control of the safety relay SR be limited to a predetermined region of car travel. This may be effected desirably by the cam-operated switch TCL1 which is cam-operated to open in the desired region. In the specific embodiment of FIG. 1, the switch TCL1 is mounted in the lower terminal region for operation by a cam TC carried by the elevator car. The switch TCL1 is biased to closed condition and is operated by the cam TC to open condition when the elevator car enters a lower terminal region. In a similar manner the cam TC may operate a switch TCU1 as the elevator car enters the upper terminal region.

Thus, if the elevator car is adjacent the lower terminal the switch TCL1 is opened. If at the same time the elevator car is traveling at a speed above a predetermined value the contacts CSDl are opened to assure the deenergization of the safety relay SR.

The car switch device CSD may be operated in accordance with the speed of the elevator car in any suitable manner. In the specific embodiment of FIG. 1, the device CSD is mounted on the penthouse floor 3. A governor GOV also is mounted on the penthouse floor for operation in accordance with the speed of the elevator car. Such operation of the governor is provided by a governor rope GOV1 which has its ends secured to the elevator car 11 and which forms an endless loop extending from the penthouse to the bottom of the hoistway. As

shown in FIG. 1, the governor rope GOV1 runs around an idler sheave GOV3 located at the lower end of the hoistway and the sheave GOVS which is employed for driving the governor in accordance with the speed of the elevator car. If the speed of the elevator car becomes excessive the governor operates to prevent further movement of the governor rope GOV1 and the resulting relative movement betwen the elevator car 11 and the governor rope GOVl operates to set a safety brake for the purpose of stopping the elevator car in a manner well understood in the art. Since the specific governor and its operation may be conventional and since its specific construction forms no part of the present invention further discussion of the governor is not necessary.

The car speed device CSD has a wheel CSDS which is coupled to a Wheel GOV7 secured to and rotating with the sheave GOVS of the governor GOV for the purpose of driving the car speed device in accordance with movement of the elevator car 11. The coupling of these two wheels may be of any suitable type. Thus, if the coupling element CSD7 were an endless chain the wheels CSDS and GOV7 would be in the form of sprocket wheels. If the coupling element CSD7 were in the form of a timing belt having teeth the wheels CSDS and GOV7 would take the fOrrn of gears. If the coupling element CSD7 were in the form of a V-belt the wheels CSD5 and GOV7 would take the form of pulley wheels.

Protection against failure of the coupling for the car speed device CSD is provided by a lever CSD9 mounted for rotation relative to the supporting structure of the car speed device CSD. This lever has at its free end a roller CSD 11 which is biased against one run of the belt CSD7. Should the belt become slack or break, the lever CSD9 rotates to operate a switch in a manner discussed below.

The car speed device CSD is shown in greater detail in FIGS. 3 and 4. It comprises a supporting structure having a base 301 and spaced pedestals 3433 and 305 rising up from the base. The pedestal 305 has mounted for rotation thereon a shaft 307. The bearings permitting rotation of the shaft relative to the supporting structure should be selected to provide as little friction as is practicable. In the specific embodiment of FIG. 3 the bearings take the form of a pair of spaced antifriction bearings of the ball-bearing type. The wheel CSD5 is mounted on the exposed end of the shaft 307 for rotation therewith.

The slack belt lever CSD9 is mounted on the end of a shaft 311 which in turn is mounted for rotation relative to the pedestal 305 about an axis parallel to and spaced from the axis of rotation of the shaft 307. Desirably the lever 311 may be mounted for rotation relative to the pedestal 305 by anti-friction bearings. Although the wheel CSD11 may be urged or biased against the driving belt by spring means, it will be assumed that gravity suffices for such biasing. Rotation of the shaft 311 is employed for operating the switch CSD3. As long as the belt is in good operating condition the shaft 311 occupies an angular position which maintains the switch CSD3 in its closed condition. Should the belt break the resultant rotation of the shaft 311 would move the switch CSD3 to its open condition. Desirably the switch CSD3 may take the form of a mercury switch.

As shown in FIG. 2 the switch CSD3 is employed for controlling the energization of the safety relay SR. Opening of the switch CSD3 deenergizes the safety relay SR. If the switch CSDS is to be effective only when the elevator car is in the lower terminal region a switch TCLZ may have its contacts connected in parallel with the switch C8133. The switch TCL2 is connected to the switch TSCLll for operation by the cam TC. The switch TCL2 is maintained in closed condition when the car is displaced from the lower terminal region. When the car enters the lower terminal region, the cam TC operates the switch T CLZ to its opened condition. Thus, if the elevator car enters the lower terminal region while the belt CSD7 is in broken condition the switches CSD3 and TCLZ assure deenergization of the safety relay SR.

Returning to FIG. 3 it will be noted that the lefthand end of the shaft 307 has secured thereto an electroconductive armature in the form of a disc 313 which is clamped to the shaft by washers 315 and a nut 317 which is in threaded engagement with the end of the shaft 307. The disc 313 is constructed of an electroconductive material such as aluminum or copper, and operates as a driving element.

The disc or driving element 313 is coupled to a driven element 319 through a fluid coupling. In the present case this fluid coupling is established by a driven element 319 in the form of a device for producing a magnetic field in which a portion of a disc 12 rotates, such as a permanent magnet. In the preferred embodiment of the invention the driven element 319 takes the form of a C- shaped permanent magnet having a high coercive force.

As an example of suitable materials the driven element 319 may be an Alnico permanent magnet. The disc 12 has a peripheral portion located between the pole faces of the permanent magnet.

The permanent magnet 319 is mounted for rotation relative to the supporting structure about the axis of the shaft 307. To this end a stub shaft 321 is secured to the pedestal 303 in alignment with the shaft 307. The driven element 319 is secured to an arm 323 which is mounted for rotation relative to the shaft 321. To maintain friction introduced by such rotation as low as possible antifriction bearings such as ball bearings 325 are employed for mounting the arm 323 for rotation relative to the shaft 321.

The driven element 319 is biased towards a predetermined position such as the lowest position which it may occupy. Although such biasing may be introduced by spring means, in the embodiment herein illustrated a weight 327 is mounted on a pin 329 which projects downwardly from the arm 323. The weight is positioned on the pin 329 by means of a nut 331 which is in threaded engagement with the pin. The distance between the weight 327 and the axis of the shaft 321 may be adjusted by rotation of the not for the purpose of adjusting the torque required for a predetermined displacement of the arm 323 about its axis of rotation.

Displacement of the arm 323 is employed for operating electrical switches. Although any desired number of switches may be operated in this manner, four switches CSDl, CSDS, CSU1 and CSUS are illustrated in FIG. 4. Inasmuch as the various switches may be of generally similar construction a detailed description of the switch CSDl will sufiice. The switch CSDl is secured to a lever 335 which is mounted for rotation on a pin 337 secured to a supporting plate 339. The supporting plate 339 in turn is secured to the supporting structure or pedestal 305. The axis of the pin 337 is parallel to the axes of the shafts 321i and 307. At its upper end the lever 335 has a roller 341 mounted for rotation about an axis parallel to the axis of the pin 337. This roller acts as a cam follower which is operated by a earn 343.

The cam 343 is mounted in any suitable manner on a cam supporting sector 345 carried by the arm 323. In the embodiment of FIG. 4, the sector 345 is provided with a slot 347 arcuate about the axis of rotation of the sector. The cam 343 is secured to the sector 345 by a bolt 349 which passes through the slot of the sector. Consequently, by loosening the bolt 349 the cam 343 may be adjusted relative to the sector 345 angularly about the axis of rotation of the sector.

The lever 335 is biased by a spring 351 to urge the roller 341 against the cam 343. Assuming that the switch CSDI is in its closed condition with the parts in the positions illustrated in FIG. 4 the elevator comes to a stop in its normal manner. However, if the elevator car is traveling at a speed above a predetermined value the earn 343 will be rotated in a clockwise direction as illustrated in FIG. 4 away from the rotor 341 and the lever 335 will be urged by its spring 351 into a position opening the switch CSDl. If at the same time the elevator car is in the lower terminal region the switch TCLI in FIG. 2 will be opened to assure deenergiz'ation of the relay SR and stopping of the elevator car. Ina similar manner each of the switches CSDS, CSUS and CSUll may be designed for operation between two conditions in response to a predetermined displacement of the sector 345.

Reviewing a. typical operation of the embodiment of FIG. 2, if the elevator car enters the lower terminal region at a speed within the desired range the torque applied by the driving element 313 of FIG. 3 to the driven element 319 is insufiicient to maintain the cam 343 displaced from the roller 341 and the switch CSDl consequently in its closed condition to assist in maintaining the safety relay SR picked up. With the safety relay picked up the elevator car comes to a stop in the manner discussed in the aforesaid Oplinger patent. However, if the speed of the elevator car as it enters the lower terminal region is above a desired value the torque applied by the driving element 313 to the driven element 319 of FIG. 3 is sufiicient to assure displacement of the cam 343 in FIG. 4 from the rotor 341 and the switch CSDI consequently is urged into its opened condition. Inasmuch as the elevator car is in the lower terminal region under the assumed conditions the switch TCLI of FIG. 2 also is open and the relay SR is deenergized to assure stopping of the elevator car promptly.

By reason of the antifriction construction of the car speed device CSD, the fluid coupling between the driving element 313 and the driven element 319, and the provision of mercury switches CSDl, CSUI, CSDS and CSUS the torque required for operation of the various switches is maintained at the lowest possible value and accurate and positive operation of the switches is assured.

For some applications the switch CSDS may be employed in suitable circuits for slowing the elevator car to a lower speed when it enters the lower terminal region at a substantial speed. The switch CSDll then may be operated to stop the elevator car.

Although the invention has been described with reference to certain specific embodiments thereof numerous modifications falling within the spirit and scope of the invention are possible.

I claim as my invention:

1. In a transportation system, a vehicle, means constraining the vehicle for movement in a predetermined path, controllable means for moving the vehicle in said path, speed-responsive means comprising a supporting struture, 'a driving element mounted for movement relative to said structure, means coupling the driving element to said vehicle for movement relative to the structure in dependence on the speed of the vehicle along said path, a driven element mounted for movement relative to said structure, means yieldably biasing the driven element towards a predetermined position, said driving and driven elements being coupled through a gap across which an electromagnetic force is transmitted by the driving element to move the driven element through a displacement dependent on the rate of movement of the driving element, control means operable from a first control condition to a second control condition, means responsive to a predetermined displacement of the driven element from said predetermined position for operating the control means from the first control condition to the second control condition, means responsive to operation of said control means for modifying the movement of said vehicle in said path, and means rendering said control means effective for modifying the movement of said vehicle only While said vehicle is within a predetermined part only of said path.

2. 'In a transportation system, a vehicle, means constraining the vehicle for movement in a predetermined path, controllable means for moving the vehicle in said path, speed-responsive means comprising a supporting structure, a driving element mounted for movement relative to said structure, means coupling the driving element to said vehicle for movement relative to the structure in dependence on the speed of the vehicle along said path, a driven element mounted for movement relative to said structure, means yieldably biasing the driven element towards a predetermined position, said driving and driven elements being coupled through a gap across which an electromagnetic force is transmitted by the driving element to move the driven element through a displacement dependent on the rate of movement of the driving element, control means operable from a first control condition to a second control condition, means responsive to a predetermined displacement of the driven element from said predetermined position for operating the control means from the first control condition to the second control condition, means responsive to operation of said control means for modifying the movement of said vehicle in said path, means rendering said control means elfective for modifying the movement of said vehicle only while said vehicle is within a predetermined part only of said path, and means responsive to a predetermined failure of said coupling of the driving element to the vehicle for modifying the movement of said vehicle in at least a predetermined part of said path.

3. In a transportation system, a vehicle, means constraining the vehicle for movement in a predetermined path, controllable means for moving the vehicle in said path, speed-responsive means comprising a supporting structure, a driving element mounted for movement relative to said structure, means coupling the driving element to said vehicle for movement relative to the structure in dependence on the speed of the vehicle along said path, a driven element mounted for movement relative to said structure, means yieldably biasing the driven element towards a predetermined position, said driving and driven elements being coupled through a gap across which a force is transmitted by the driving element to move the driven element through a displacement dependent on the rate of movement of the driving element, a first one of said elements comprising an electroconductive member concentric and movable about an axis, a

second one of said elements comprising means for establishing a magnetic field within which a portion of said electroconductive member is located, said second one of said elements being mounted for rotation about said axis whereby relative rotation of said elements about the axis develops an eddy-current-produced force which urges the driven member about said axis, a plurality of electrical switches each having a conductive condition and a non-conductive condition, each of said switches having operating means including 'a cam follower operable for actuating the associated switch from one to the other of said conditions, cam means engaging said cam followers to operate said switches respectively in response to different displacements of said driven element in one direction from said predetermined position, and means responsive to operation of one of said switches for modifying the movement of said vehicle in said path.

4. A speed-responsive device comprising a supporting structure, an electroconductive element concentric about an axis and mounted for rotation relative to the structure about said axis, a magnetic-field-producing element mounted for rotation relative to the structure and relative to the electroconductive element about said axis, said field-producing element establishing a magnetic field through which a portion of the electroconductive element moves in response to relative rotation of said elements, a wheel member coupled to 'a first one of said elements and effective when rotated relative to the structure for rotating said first one of said elements about said axis relalative to the structure, biasing means coupled to a second one of said elements for yieldably biasing said second one of said elements about said axis towards a predetermined position, an electrical switch having a conductive condition and a nonconductive condition, said switch ineluding an operating member, and operating means responsive to a predetermined displacement about said axis against said biasing of said second one of said elements for actuating the operating member to operate the electrical switch between said conditions.

5. A device as claimed in claim 4 wherein said elements are mounted respectively on two separate shafts spaced axially along said axis, said supporting structure comprising a U-shaped member, each of said shafts being secured to a separate one of the arms of said U-shaped member.

6. A speed-responsive device comprising a supporting structure, an electroconductive element concentric about an axis and mounted for rotation relative to the structure about said axis, a magnetic-field-producin'g element mounted for rotation relative to the structure and relative to the electroconductive element about said axis, said field-producing element establishing 'a magnetic field through which a portion of the electroconductive element moves in response to relative rotation of said elements, a Wheel member coupled to a first one of said elements and effective when rotated relative to the structure for rotating said first one of said elements about said axis relative to the structure, biasing means coupled to a second one of said elements for yieldably biasing said second one of said elements about said axis toward a predetermined position, a mercury electrical switch having a conductive condition and a non-conductive condition, said switch including an operating member, and operating means responsive to a predetermined displacement about said axis against said biasing of said second one of said elements for actuating the operating member to operate the electrical switch between said conditions, said operating member comprising a cam follower, and said second one of said elements comprising a cam mounted to operate the cam follower in response to said predetermined displacement, a lever mounted for rotation relative to said structure about a second axis parallel to and radially spaced from the first-named axis, said lever having an arcuate surface tangent to 'a line which is also tangent to said Wheel, said lever being biased about said second axis towards a predetermined position, and switch means operable in response to a predetermined displacement of said lever about the second axis against its bias.

References Cited UNITED STATES PATENTS 982,074 1/1911 Larson 318372 X 1,054,923 3/1913 Kenny 318-369 2,278,120 3/1942 Schwarz 3l8372 X 2,874,806 2/ 1959 Oplinger 187-29 ORIS L. RADER, Primary Examiner.

THOMAS E. LYNCH, Examiner. 

